The present invention relates in general to an impulse valve and in particular to an impulse valve having two electromagnetically operated preliminary control valves, a housing with a control piston which is shiftable in a working chamber and cooperating with the preliminary control valves in such a manner that is adjusted position remains unchanged even if the preliminary control valves are inactivated, and the housing further defining an inlet port, a pressure-relieving port and two working ports, for example.
In an impulse valve only a short electrical impulse is applied to the selected preliminary control valves in order to switch over a control position of the main piston; the switching movement is effected in a very short time interval and the main piston, after being shifted from one control position into another one, retains the changed position even after the control impulse is terminated, that is, even after the corresponding preliminary control valve is deactivated. This condition is repeated in each changeover of the control position of the main valve.
In this manner it is achieved that during the time interval in which the main control valve is adjusted in one or the other control position, no energy is to be applied to the preliminary control valve, and consequently the energy for activating the solenoids is saved.
Known embodiments of multi-way impulse valves have voluminous constructions and are expensive in manufacture.